Add sane defaults for git-gutentags

dotfiles/vim/vimrc

 let g:netrw_banner=0
 let g:netrw_liststyle=3
 
+let g:gutentags_exclude_project_root=['/home/amahdal/vcs.tests/distribution']
+let g:gutentags_ctags_tagfile='.git/tags'
+
 let g:local_vimrc=".vimrc_local.vim"
 let python_highlight_all = 1
 let g:vim_markdown_folding_disabled=1